Speaker
Description
Following molecular dynamics during the temporary evolution of kinetically changing samples is a major challenge. With recent developments of analysis frameworks, accessing the short-time self-diffusive properties of protein solutions by measuring specific energy transfers via neutron backscattering, kinetically changing samples can be investigated. The immobile fraction, determined by multi-dimensional fits of full QENS spectra, can be assigned to proteins in a gel-like state or in crystals [1]. Using time-dependent neutron spin echo measurements at different momentum transfers q, we access the collective diffusion during the crystallization process in different phases of the sample.
Here, we discuss the results of a recent protein crystallization study. CdCl2 induces a non-classical crystallization process [2,3] of BLG with a metastable intermediate phase. We investigated the short-time collective and self-diffusion of BLG by neutron spin-echo (IN11), FWS and QENS (IN16b), respectively, of the crystallization process for different sample conditions. Combining the different results, a consistent picture of the process can be obtained, which differs significantly from classical BLG crystallization induced by ZnCl2[1]. This implies a strong influence of seemingly subtle cation-specific effects on protein crystallization.
[1]C. Beck et al., Cryst. Growth Des. 2019
[2]A. Sauter et al., J. Am. Chem. Soc. 2015
[3]A. Sauter et.al., Faraday Discuss. 2015
